Preparation of oxirane compounds by autoxidation

ABSTRACT

Boron and Lithium phosphate have been found to provide high selectivity to epoxides in the autoxidation of olefinic compounds when said phosphates are employed in catalytic amounts. Selectivities for the epoxide as high as 65.8% have been achieved at conversions of about 14 mole %.

United States Patent Barone Aug. 12, 1975 54 PREPARATION 0F OXIRANE COMPOUNDS 3,259,638 7/1966 Allison 260/348.5 v 3,351,635 7/1967 Kollar 260/348.5 L

BY AUTOXIDATION Inventor: Bruno J. Barone, Houston, Tex.

[73] Petra-Tex Chemical Corporation,

Houston, Tex.

Filed: Sept. 28, 1973 Appl. No.2 401,781

Related US. Application Data Division of Ser. No. 170,283, Aug. 9, 197i.

Assignee:

US. Cl... 260/348.5 V; 260/597 R; 260/604 R;

260/610 B Int. Cl. .1 C07d l/12 Field of Search 260/348.5 V

References Clted UNITED STATES PATENTS 3,187,055 6/1965 Armstrong et al. 260/610 B Primary Examiner-Norma S. Milestone Attorney, Agent, or FirmN. Elton Dry; Kenneth H. Johnson 57 ABSTRACT ide as high as 65.8% have been achieved at conversionsof about 14 mole 8 Claims, No Drawings 1 OF OXIRANE COMPOUNDS BY AUTOXIDATION This is a division of application Ser. No. 170,283,

filed Aug. 9, 1971. r v 1 BACKGROUND OF THE INVENTION The present invention .relates to the preparation of olefin oxides and in particular relates to new catalysts for use in the process of autoxidation of ethylenically unsaturated organic compounds to the corresponding oxirane compounds.

A number of catalysts have beenemployed in the liquid phase oxidation of ethylenically unsaturated organic compounds. U.S. Pat. No. 3,259,638 shows the use of compoundsof Groups IV-A, V-A or Vl-A of the Periodic Table excluding chromium. Selectivity for the epoxide with each catalyst was lessthan 50%. The major by-products were epoxy-alcohols. The general disadvantages ofthe prior methods, particularly the catalysts employed in such'autoxidations were long reaction times, low conversions and low selectivity to the epoxide, i.e., usually less than 50%. The term autoxidation is understood to mean the reaction of a substance with molecular oxygen without the intervention of a flame. In addition to the epoxide a number of byproducts are possible from the autoxidation of olefins, e.g., epoxy-alcohols, diols, olefin hydroperoxides, aldehydes, ketones, water and carbon dioxide. If the desired product is the epoxide thenthe production of such by-products and the necessity of separating them from the epoxide can make the process economically unattractive. The by-products are often quite useful, e.g., acetone is a common product and the uses of ace tone are well known, however, acetone is a far less valuable material than many of the common or desirable olefinic starting materials. 1

It is an object of this invention to provide an improved process for the autoxidation of ethylenically unsaturated organic compounds. It is a further object of this invention to provide a process which has high selectivity for epoxides. These and other objects will become apparent from the discussion below.

DESCRIPTION OF THE INVENTION It has been found'that ethylenically unsaturated organic compounds can be autoxidized to oxirane compounds by a process comprising contacting an ethylenically unsaturated organic compound with molecular oxygen in liquid phase inthe-presence of a catalytic amount of lithium phosphate or boron phosphate. The amount of phosphate is generally about 0.05 to about 0.8 weight percent based onthe olefinic starting material, more preferably an amount in the range of 0.1 to 0.4 weight percent of phosphate on the same basis. The total amount of phosphate can be added to the reaction initially or it can be added incrementally throughout the reaction. The presence of other known catalysts, such as vanadium naphthenate, tungstic acid. niobium pentoxide, vanadium pentoxide, molybdenum hexacarbonyl, cobalt naphthenate, chromium naphthenate and the like, which are used for the preparation of epoxides has not been found to be detrimental, however. no advantage has been observed in this regard.

The present reaction is an autoxidation carried out at somewhat elevated temperatures. Generally the temperatures which are most suitable for the oxidation will PREPARATION be between about 70-l40C. and more preferably.

about -1 10C. In autoxidations there is usually an induction period during which the reaction proceeds very slowly. During this period the production of epoxideis slow, however, the induction period can be reduced by the use "of high initial temperatures, i.e., C. However, once the reaction is initiated the temperature is reduced, e.g., 7()l 20C. Temperatures higher than 120C should not be employed after the reaction has been initiated since the possibility of further oxidation is enhanced.

The induction period mentioned above can also be reduced by the addition of an initiator such as some of the hydroperoxide by-product which may be produced. Other initiators are free radical initiators such as a-rnethy l. benzyl hydroperoxide, a-methyl-pmethylbenzenyl hydroperoxide, a-methyl-a-n-propylp-xylylene dihydr operoxide, ethyl acetoacetate, phenylacetone, acetylacetone and the like.

The autoxidation is carried out by contacting an olefinically unsaturated compound in liquid phase at the temperatures and conditions set out herein with molecular oxygen. The oxygen can be furnished as pure oxygen with inert gases, such as helium or nitrogen in the same or substantially different proportions as oxygen is found in air.

Sufficient pressure is employed so as to maintain the reaction mixture in liquid phase. This will usually require more than atmospheric pressure, although some of the hydrocarbons encompassed herein are liquid at atmospheric pressure at temperatures up to the 120C. maximum. Generally, however, pressure will be required. It is not necessary to use any more pressure thanis necessary to maintain the liquid phase since oxygen is not believed to be the rate determining factor in the reaction. Pressures of atmospheric up to about 1000 psi will usually be sufficient.

The reaction is performed under liquid phase conditions and, preferably, the ethylenically unsaturated compound is employed in excess and conveniently serves as the reaction solvent. If desired, however, other solvents which are inert to the oxidation conditions can be employed such as the esters of aliphatic alcohols and carboxylic acids, hydrocarbons, saturated ethers and alcohols, waterand mixtures thereof. In general, any organic liquid that is inert to the reactants and to the oxidation conditions can be employed for the reaction solvent in my invention. Generally it is convenient to employ organic liquids having from 1 to about i 25 carbons; preferably solvents having from 1 to 6 carbons are used. Illustrative solvents of the aforementioned classes include the following esters: methyl acetate, ethyl acetate, n-propylpropionate, isopropyl acetate, ethylpropionate, n-butylbutyrate, sec-butyl acetate, isobutylacetate, ethyl-n-butyrate, n-butyl acetate, isoamyl acetate, n-amyl acetate, glycol diformate, furfural acetate, isoamyl n-butyrate, ethyl-acetyl acetate, diethyl oxalate, glycol diacetate, isoamyl isovalerate, n-dibutyl oxalate, etc.

Various aliphatic hydroxy compounds can be employed such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, amyl alcohol, isoamyl alcohol, hexanol, isohexanol, heptanol, isoheptanol, 3- methyhexanol-l, lauryl alcohol, 3,4-diethylheptanol-l, 4-eth ylhexanol ethylene glycol, propylene glycol, etc.

Various ethers can also be employed including the ethers of the aforementioned aliphatic alcohols such as methyl ethyl ether, diethyl ether, dioxane, diisopropyl ether, diisoamyl ether, diethylene glycol diethyl ether,

tetraethylene glycol dimethyl ether, ethyl heptyl ether,

isobutyl amyl ether, lauryl ethyl ether, etc.

Hydrocarbons including the saturated and aromatic such as isopentane or hexane, preferably without a diluent by passing a stream of 2,3-epoxy-2-methylbutane through a bed of acid catalyst at temperatures of 200 to 400C. and 15 to l000 p.s.i.g. The acid catalysts suithydrocarbons can of course be employed as suitable 5 ably used for simultaneous, isomerization and dehydrainert solvents, e.g., pentane, hexane, heptane, octane, tion are, such as acidic metal, e.g., alumina, chromia, isooctane, decane, dodecane, kerosene, naphtha, benthoria and titania oxides; siliceous refractory oxides, zene, xylene, toluene, cumene, isocumene, naphthae.g., silica-alumina, silica-magnexia, silica-titania and lene, etc silica-magnesia-zirconia; and alkali and alkaline earth In addition other inert diluents such as the nitro or metal Phosphates, -glithium Phosphate and magnehalo substituted hydrocarbons are suitable, e.g., nitro- Slum Phosphate benzene, trichlorobenzene, carbon tetrachloride and in r y g Out the pr s of the n ention an olefinthe like. ically unsaturated compound and oxygen are contacted The ethylenically unsaturated compounds which may in the Presence of the P p e eataiyst- [t has been be epoxidized by the process of the invention include found Convenient to carry out this Contacting y substituted and unsubstituted aliphatic and alicyclic Persing the catalyst in the liquid Phase and Passing the olefins which may be, for example, hydrocarbons 3 gas containing molecular oxygen illtO this mixture. The te al ohol ketone or ethers, catalyst is easily separated from the other materials A wide variety of ethylenically unsaturated co since it is a solid in the reaction. The process is as easily pounds can be epoxidized in accordance the pro. adapted to either batch OI continuous process operacess. In general, any organic olefin, preferably a hydrotion using Conventional q p carbon having from 2 to about 30 carbon atoms can be The following examples will illustrate the operation oxidized, preferably 3 or more carbon atoms, more of the invention and the advantages to be derived preferably olefinically unsaturated compounds having therefrom The apparatus used in each of the following from 3 to 12 carbon atoms are oxidized. The aliphatic examples was a 3,000 P magnetically Stirred, liter, hydrocarbon l fi i ethykme, prom stainless steel autoclave, equipped with a Dispersamax [ene, butene l b q isobutene pente J agitator, reflux condenser and internal water cooling {gene-2, h i h h 3- h lh v coil. The olefinic feed, and other materials for the reacoctene-l, isooctene, nonene, decene, dodecene, tridection were charged to the t r- Oxygen C ntaining ene, pentadecene, octadecene, eicosene, docosene, gas was added continuously with sufficient pressure to tricosene, tetracosene, pentacosene, styrene, methyl maintain the liquid P Inlet gas was measured y styrene, vinyl toluene, etc. Examples of hydrocarbon following the Pressure h p in a Standardized metering diolefins which can also be oxidized include: pentadi- Vessel and fed into the autoclave through a ballast y ene, hexadiene, oxtadiene, decadiene, tridecadiene, Pressure g to Exit gas. at mospheric pressure eicosadiene, tetracosadiene, etc. The alicyclic olefins was Passed through three y lee traps, an aseal'ite are illustrated by cyclopentene, cyclohexene, cyclotrap, a Wet test meter and then Ventedwas heptene, methylcyclohexene isopmpylcydohexene, ,ployed in the present examples unless otherwise indibutylcyclohexene, octaylacyclohexene, dodecylcy cated. In the runs using air a Beckman E-2 oxygen anaclohexene, vinyl cyclohexene, phenyl cyclohexene, etc. lyzer as inserted after the dry ice traps and the oxygen Olefins having halogen, oxygen, sulfur and other sim- 40 vcontent of the off gases monitored so that the reaction ilar substituents may be used. Such substitued olefins was not xygen tar his Can be a ided by adjustare, u h as, methyl-methacrylate h l oleate, i'ng the gas flow to provide a minimum oxygen content methyl vinyl ketone and allyl chloride. In general all f the Off g eg. mo e han about 3 vol. Analyolefinic materials within the ranges specified, which SiS s by gas Chromatograph. Epoxide content was dehave been epoxidized by the methods of the previously termined by both gas chromatography and the chloroused, including unsaturated polymers can be epoxihydrin chemical method described in Organic Analysis dized by the process of the invention. lnterscience Publishers, N. Y. 1953, Vol. 1, page 134.

The epoxides produced by this invention have a great deal of utility in the preparation of epoxy resins or in EXAMPLES other resins where coupling or crosslinking is desirable. In a particular case the epoxide produced is the precur- These examples demonstrate both theboron phossor of a valuable diolefin, e.g., 2-methyl butene-2 is oXiphate and lithium phosphate catalysts. The range of the dized to 2,3-epoxy-2-methyl butane by the improved Examples demonstrates a number of the variables for process of the present invention. The 2,3-epoxy-2- the operation of the process. The oxidation was carried methylbutane is isomerized to the allylic alcohol form out with air at 400 p.s.i., except for Example 8 and 9 and dehydrated to isoprene, which is used to prepare which employed oxygen at 600 psi Examples 8 and 9 polyisoprene a highly desirable rubber. The 2,3-epoxyare controls. Example 7 compares phosphoric acid to Z-methylbutane can be concurrently isomerized and the catalysts. Example 5 shows the addition of a condehydrated in liquid phase, with or without a diluent 6O ventional vanadium catalyst to the boron phosphate.

TABLE Example No. l 2 3 4 S 6 7 8* 9* l0 Reactants 2-Methylbutene-2,g. 500 500 500 500 500 500 500 500 500 500 Boron Phosphate, g. 1.0 1.0 1.0 2.0 1.0 1.0

TABLE Cntinued Example No. 1 2 3 4 5 6 7 8* 9* 10 Phosphoric Acid. g 0.5 Vanadyl Acetylacetonate, g. 0.2 Lithium Phosphate, g. 0. Reaction Conditions Temperature. "C 90 90 100 100 90 90 90 90 90 90 Total Reaction Time. Hrs. 4.25 3.33 3.42 1.48 4.17 5.63 4.50 3.50 2.03 7.67 Results lnduction Period, min. 154 62 172 30 77 106 1 18 138 73.5 Oxygen Consumed, mole 0.692 1.308 0.815 0.851 1.221 1.581 0.706 2.302 0.917 0.945 Carbon Dioxide Produced. 0.003 0.001 0.002 0.002 0.001 0.003 0.010 0.051 0.009 0.003 mole 2-Methylbutene-2 8.8 13.8 7.7 9.6 11.5 22.2 6.9 33.9 9.4 7 3 Conversion mole 70 Selectivity (Mole Product/100 Mole Olefin Consumed) Acetaldehyde 10.7 3.5 5.6 11.8 9.6 8.9 12.4 24.2 29.5 7.3 Acetone 15.4 12.8 14.1 23.4 18.9 22.9 23.8 41.6 36.9 13.7 Methyl lsopropyl Ketone 3.7 4.3 3.8 2.5 5.5 1.3 8.1 1.6 1.5 9.6 2,3-Epoxy-2-Methylbutane 52.9 65.8 59.8 48.3 65.3 49.2 25.7 13.8 10.9 ,9 2-Methylbutane-2,3-diol 5.7 2.1 5.2 5.6 2.3 (a) (a) (a) (a) (a) Olefin Hydroperoxide 14.8 12.7 14.6 14.9 5.1 20.2 27.5 30.2 38.5 8.5

The invention claimed is; cylcyclohexene. vinyl cyclohexene and phenyl cyclol. A process for the autoxidation of ethylenically unhexene' saturated hydrocarbon compounds containing from 2 T Process accordmg to clam 4 wherem the to carbon atoms to produce oxirane compounds, ylenlcally unsaturated hydrocarbon has 3 to 12 carbon said process comprising contacting said hydrocarbon atoms' compounds with molecular oxygen in the prese of 6. The process accordmg to claim 3 wherein the ethmhium phosphate at a temperature of from about ylemcally unsaturated hydrocarbon has 5 carbon 70C. toabout 120C. and a pressure sufficient to 30 atomsmaintain said hydrocarbon compounds in liquid phase, ProceSS 0f P P Oxlrane compounds by said lithium phosphate being present in an amount f autoxidation of ethylemcally unsaturated hydrocarbon from about 0.05 to about 0.8 weight percent based on Compounds contammg from 3 to 12 carbon atoms Said hydrocarbon compounds prising contacting said hydrocarbon compound in liqg5 uid phase with molecular oxygen in the presence of a 2. The process according to claim 1 wherem the tem- 0 c o 0 catalyst at 70 to 120 C. at a sufficrent pressure to perature is from about 80 C. to about 1 10 C.

maintain sald liquid phase wherein the improvement 3. The process accordmgto claim 1 wherein the 11th comprises lithium phosphate in a quantity of from Phosphate Present 3" amount of to about 0.05 to about 0.8 weight percent based on the weight Percent 40 weight of said hydrocarbon compounds as said catalyst. 4. The process according to claim 1 wherein the eth- 8. A process for the autoxidation of Z-methyl buteneylehic'ally unsaturated organic hydrocarbon is selected 2 to produce a product comprising 2,3 epoxy-2- 'fidifi the group consisting of ethylene, propylene, bumethylbutene, said process comprising contacting said {one-.1, bu =g., isobutene, m n m q, d 2-methy1-butene-2 with molecular oxygen in the prescene, dodecene, tridecene, pentadecene, octadecene, ence of a catalyst comprising lithium phosphate at a eicosene, docosene, tricosene, tetracosene, pentacotemperature of from about 70C. to about 120C. and sene. styrene, methyl styrene, vinyl toluene, pentadia pressure sufficient to maintain said Z-methyl-buteneene, hexadiene, octadiene, decadiene, tridecadiene, 2 in liquid phase. a t m phosphate being present eicosadiene, tetracosadiene, cyclopentene, cyclohex in an amount of from a ut -0 0 a out 0.8 weight 'ene. cycloheptene, methyl cyclohexene, isopropylcy- 5 Percent based Said hyI- tene-Z. clohexene, butylcyclohexene, octylcyclohexene, dode- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3,899,518 DATED I 3 August 12,

|NVENTOR(S) Bruno]. Barone It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, Line 58 reads "desirable rubber" but should read -desirable synthetic rubber Table footnotes omitted, should read 600 psi oxygen pressure (A) trace Col. 6, Line 38 reads "comprises lithium phosphate" but should read -comprises using lithium phosphate Signed and Sealed this third Day Of February 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Atlesting Officer Commissioner ofParenrs and Trademarks 

1. A PROCESS FOR THE AUTOXIDATION OF ETHYLENICALLY UNSATURATED HYDROCARBON COMPOUNDS CONTAINING FROM 2 TO 30 CARBON ATOMS TO PRODUCE OXIRANE COMPOUNDS, SAID PROCESS COMPRISING CONTACTING SAID HYDROCARBON COMPOUNDS WITH MOLECULAR OXYGEN IN THE PRESENCE OF LITHIUM PHOSPHATE AT A TEMPERATURE OF FROM ABOUT 70*C, TO ABOUT 120*C. AND A PRESSURE SUFFICIENT TO MAINTAIN SAID HYDROCARBON COMPOUNDS IN LIQUID PHASE, SAID LITHIUM PHOSPHATE BEING PRESENT IN AN AMOUNT OF FROM ABOUT 0.05 TO ABOUT 0.8 WEIGHT PERCENT BASED ON SAID HYDROCARBON COMPOUNDS.
 2. The process according to claim 1 wherein the temperature is from about 80*C. to about 110*C.
 3. The process according to claim 1 wherein the lithium phosphate is present in an amount of 0.1 to 0.4 weight percent.
 4. The process according to claim 1 wherein the ethylenically unsaturated organic hydrocarbon is selected from the group consisting of ethylene, propylene, butene-1, butene-2, isobutene, pentene-1, pentene-2, decene, dodecene, tridecene, pentadecene, octadecene, eicosene, docosene, tricosene, tetracosene, pentacosene, styrene, methyl styrene, vinyl toluene, pentadiene, hexadiene, octadiene, decadiene, tridecadiene, eicosadiene, tetracosadiene, cyclopentene, cyclohexene, cycloheptene, methyl cyclohexene, isopropylcyclohexene, butylcyclohexene, octylcyclohexene, dodecylcyclohexene, vinyl cyclohexene and phenyl cyclohexene.
 5. The process according to claim 4 wherein the ethylenically unsaturated hydrocarbon has 3 to 12 carbon atoms.
 6. The process according to claim 3 wherein the ethylenically unsaturated hydrocarbon has 5 carbon atoms.
 7. In the process of producing oxirane compounds by autoxidation of ethylenically unsaturated hydrocarbon compounds containing from 3 to 12 carbon atoms comprising contacting said hydrocarbon compound in liquid phase with molecular oxygen in the presence of a catalyst at 70* to 120*C. at a sufficient pressure to maintain said liquid phase wherein the improvement comprises lithium phosphate in a quantity of from about 0.05 to about 0.8 weight percent based on the weight of said hydrocarbon compounds as said catalyst.
 8. A process for the autoxidation of 2-methyl butene-2 to produce a product comprising 2,3 epoxy-2-methylbutene, said process comprising contacting said 2-methyl-butene-2 with molecular oxygen in the presence of a catalyst comprising lithium phosphate at a temperature of from about 70*C. to about 120*C. and a pressure sufficient to maintain said 2-methyl-butene-2 in liquid phase, said lithium phosphate being present in an amount of from about 0.05 to about 0.8 weight percent based on said 2-methyl-butene-2. 